Heading abroad from the U.S. this summer? Consider packing a few extra dollars. Since early March, the greenback has fallen 11% against the euro and 17% against Britain's pound as investors who had sought out the dollar as a safe haven during the worst of the crisis now head for riskier assets. Throw in concerns over the U.S.'s spiraling deficit and calls from China for an alternative reserve currency, and "the likelihood is the dollar's going to remain under pressure," says Simon Derrick, head of currency research at Bank of New York Mellon in London. "You're going to see it continue to slide." (Watch TIME's video of Peter Schiff trash-talking the markets.)

That's a reversal from the recent uptick. Traditionally a safe bet amid economic mayhem, the dollar climbed about 25% against the euro in the eight months to March this year; the unattractiveness of rival currencies only made it more appealing. But, says Derrick, "that drive seems to be shifting substantially." Sure, a hint of bleak economic data can still goose the greenback  the prospect of poor U.S. payroll figures for June, set for release Thursday, has helped boost the currency in recent days  but optimism in other assets is on the rise. Global equity markets, in particular those in emerging-market countries, have performed well in recent months. China's Shanghai composite index, for instance, has shot up 63% so far this year.

Also weighing on the dollar: investor concerns that to balance a budget deficit expected to swell this fiscal year to $1.85 trillion  equal to 13% of the country's GDP, a level not seen since World War II  the Federal Reserve could simply resort to printing more money, further flooding the markets with dollars. While the central bank said on June 24 that it had no plans to expand its purchase of government or mortgage bonds beyond the $1.2 trillion earmarked for the purpose in March, not everyone is convinced. "There is always the nagging concern that if this is just a dead cat bounce in the equity markets and we have a further rocky ride in the second half of this year," says Derrick, "then a second round of fiscal spending programs may have to be introduced." (Read "Is the Almighty Dollar Doomed?")

Bottom line: the dollar faces a longer-term challenge, and the big players know it. Echoing a call made by Zhou Xiaochuan, its governor, in March, China's central bank advocated a new global reserve currency in its annual financial-stability report released last Friday. Raising concerns of a move away from the dollar as the world's reserve, the proposal for a "super-sovereign" coin nudged down the greenback vs. a host of major currencies. That may have been a tad more impact than Zhou was seeking: with something like two-thirds of China's roughly $2 trillion of foreign-currency reserves held in dollars, the lower a buck goes, the less China's vast pot of cash is worth.

In reality, with 64% of the world's reserves held in dollars at the end of last year  way more than in any other money  a move to a new reserve currency would be both time-consuming and complicated. And since China holds so many dollars, selling even a small amount of its reserves would dent the value of those that remained. But despite the glitches, argument over the need for a new international reserve does little to lift sentiment in the dollar's favor. Its replacement might be an "implausible suggestion," analysts at HSBC wrote in a May note to clients, but "its pre-eminent position as the reserves currency of the world does not mean that [the dollar] will maintain its value." Like Derrick, HSBC is counting on a further fall in the months ahead. Better not leave that holiday too late.